#! /usr/bin/bash
#-----------------------------------------
#               sketch-1                 |
#-----------------------------------------

#----------- Create variable -------------
SayHello="Hello world!"
echo $SayHello
#----------- Delete variable -------------
unset SayHello
echo $SayHello
#------------- Return value --------------
#ls a
#echo $?
echo $$
sleep 20 &
echo $!
fg 
read str
echo str is $str

